1. Technical Field
Various embodiments of the present disclosure relate generally to semiconductor devices and, more particularly, to varactors and semiconductor integrated devices including the same.
2. Related Art
Capacitors have been employed in various integrated circuits, and varactors have been used in some application areas of electronic circuits. A varactor, which is also referred to as a variable capacitor, may exhibit tunable capacitance values. For example, a capacitance value of the varactor may be controlled or varied by changing a voltage applied between both terminals of the varactor. A varactor may be used in analog circuits or digital circuits for tuning parameters of other circuits.
A varactor may be realized to have a metal-oxide-semiconductor (MOS) structure or a PN junction structure. A varactor having a MOS structure (hereinafter referred to as a MOS varactor) has the advantage of being compatible with MOS fabrication processes. For example, a MOS varactor may be formed using the same process as used in fabrication of metal-oxide-semiconductor field effect transistors (MOSFETs) even without additional unit processes. Moreover, it is well known in the art that generally a MOS varactor has a wider tuning range and a higher quality (Q) factor as compared with a varactor having a PN junction structure.